<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">
        function fun() {
            alert(arguments.length)
            alert("无参函数fun()")
        }
        fun(12,3);
    </script>
</head>
<body>

</body>
</html>